[ Pobierz całość w formacie PDF ]
.46 ZINNIATrials began in 1952 with an experimental High Frequency (HF) ionospheric radar called Orange Poodle to detect aircraft flying beyond the radar horizon, at ranges of up to 120miles.47 A later Zinnia I set was used against subsonic aircraft, but was further developedto detect high velocity targets, such as missiles (Zinnia III).Zinnia II was a UK-produced, continuous-wave (CW) version of an American pulse radar called Chaplain ,used for monitoring their own nuclear tests and missile firings.48 Trials of both Zinnia IIand Chaplain took place in the UK between May and July 1959, and one observation wascorrelated with the Soviet missile test range at Kapustin Yar.Further trials of Zinnia IIand III were carried out in the United States (Project Bart ) between October 1959 andJanuary 1960, using American Atlas, Jupiter, Thor, Polaris and Titan ballistic missiletests as targets, as well as Snark and Mace cruise missiles.Detections were achieved atranges of up to 1,800 km by means of doppler shifts between transmitted and receivedfrequencies.To begin with, interest in these theoretical experiments was for an intelligence-gathering application, but as work progressed their potential for early warning became Britain and ballistic missile defence 1942 2002 86clear.49 Following the successful experiments in the United States, it was decided toproduce an engineered version , codenamed Sandra , for intelligence purposes (ASR2209).50 This was to be located in Cyprus from where the three main Soviet test rangescould best be monitored.Capital expenditure was under £½ million with annual runningcosts of £205000 £35,000.In view of increased awareness of the scale of the Russianmissile development programme, urgency for the deployment of the equipment isalready high and is mounting rapidly.Its performance was assessed as greatly superior tothe American Chaplain system.Cyprus was not, however, the best location from which to detect operational IRBMlaunches from the Baltic States, for which a UK site would be better suited.51 RAE ZinniaII trials were still continuing in Britain.This experimental equipment was less accuratethan the developed Sandra version, but subject to fewer false alarms.52 Like Jodrell Bank,it could only cover a limited sector, making the two interim early warning proposalscomplementary rather than alternatives.53Project Sandra became operational in Cyprus in July 1962, and was used for earlywarning as well as intelligence gathering until BMEWS became operational in early1964.54 Budgetary constraints as well as the short period for which it was required meantthat the UK-based interim proposal was not proceeded with, though HF over-the-horizon(OTH) radar trials continued at Orfordness in Suffolk until the mid-1970s.55 AmericanOTH radars known as System 440L and 441A, were scheduled for service in 1969 and1971/72 respectively,56 following agreement in 1966,57 but never actually saw operationalservice.58 OTH radars could not track missiles or provide impact point prediction.59 Theexperimental set detected the first Chinese nuclear test in 1964, though this was initiallyassessed as a missile launch which indicates the ambiguity of much of the informationderived from such systems.60MIDASPreliminary research into infra-red detection of ballistic missiles during their ascent phasewas carried out at RRE in the mid-1950s.This work assumed an airborne sensor, fromwhich detection ranges of 600 miles for liquid fuel rockets and 2,000 miles from thehotter solid fuel missiles might be achieved.61 No plans were made, however, to developan operational system.The idea was examined again in 1961, but it was concluded thatan airborne system offered no additional warning to that which was expected from the USMissile Defense Alert System (MIDAS) satellite-based system, an agreement on whichhad just been reached.62In June 1959 the US Air Force made an informal approach to the Air Ministry aboutthe possibility of siting one of three ground stations for the projected MIDAS in theUK
[ Pobierz całość w formacie PDF ]